3 1 6 Cellulose 



under all conditions of treatment, especially in regard to the very 

 important question of ' stability,' and the uses of these products 

 as explosives. (Cross, Bevan, and Jenks. Berl. Ber. 34, 2496.) 



The highest derivative in this series of esters being the 

 trinitrate on the C 6 formula the fact is shown to be consistent 

 with the presence of 4.OH groups in the cellulose unit, which 

 now must be taken as finally established by the general recog- 

 nition of the highest acetate as a tetracetate, and as a true 

 cellulose derivative. A higher degree of acetylation implies a 

 hydrolysis of the cellulose, which is confirmed by a study of the 

 properties of such derivatives. These conclusions have been 

 verified and extended by the later investigations of Z. H. Skraup 

 of the acetylation of starch and cellulose. (Berl. Ber. 1899, 2413.) 

 In regard to the lower limits of acetylation it is stated in this 

 volume (p. 35, ist ed.) that the normal celluloses do not react with 

 acetic anhydride at its boiling temperature. Investigations by the 

 authors have shown that this statement, current in the text-books, 

 is erroneous; a mono-acetate (C) is formed under these condi- 

 tions. This product is insoluble in all the solvents of the cellulose 

 esters, and moreover resists the action of cuprammonium solutions. 



The authors have further investigated the benzoat'es of 

 cellulose, and the conditions of their formation by interaction 

 of cellulose and benzoyl chloride in presence of alkalis. From 

 these esters mixed esters have been obtained by the action of 

 nitrating acid. The benzoyl residues are converted into nitro- 

 benzoyl, and further reaction ensues with the residual OH groups 

 of the cellulose. 



The following conclusions appear to be justified : the highest 

 benzoate is the dibenzoate, or on the C 12 unit the tetrabenzoate. 

 Taking 8.OH groups as the maximum in this unit, five only react 

 in these mixed esters, as compared with six as a maximum in the 

 simple nitric esters. (See ' Researches on Ce^ulose,' pp. 34-40.) 



From points of view other than the purely theoretical, various 

 and important investigations of cellulose esters have been published 

 in recent years. 



Lunge and Bebie have carried out an elaborate enquiry into 

 the constants of nitration of the normal cellulose ; chiefly concern- 

 ing the yields and composition of the nitrates under definite varia- 

 tions of the more important chemical and physical conditions of 

 the reaction. The results constitute the most extensive series of 

 numerical records hitherto published, for which the original papers 

 must be consulted. (Ztschr. Angew. Chein. 1901, 483. See also 

 O. Guttmann, Chem. Ztschr. I. No. 12.) 



